Systems and methods for prevention of condensation of ambient water vapor due to evaporation of frozen carbon dioxide particles used to clean data storage tapes. Various embodiments maintain conditions under which condensation cannot form in the ambient environment immediately surrounding a portion of a rigid surface on which the tape is maintained in thermodynamic contact and under tension (e.g., a metallic capstan around which the tape is wrapped).
Legal claims defining the scope of protection, as filed with the USPTO.
1. A system for reducing condensation on data storage tape during carbon dioxide cleaning, comprising: a) at least one rigid surface in which the tape is supported under tension over a contact distance; b) a carbon dioxide delivery system, comprising at least one nozzle per rigid surface, each nozzle directed to strike the tape at an impingement point within the contact distance of its respective rigid surface; c) a heating system to maintain surface temperature of the tape, as measured near each impingement point, above ambient dew point.
2. The system of claim 1 , in which the rigid surface comprises a material chosen from the group consisting essentially of nickel, iron, copper, beryllium, chromium, steel, zinc, aluminum, silver, magnesium, and their alloys.
3. The system of claim 1 , in which the rigid surface is a capstan, and the contact distance is a wrapping angle.
4. The system of claim 1 , further comprising at least one environmental chamber separating the rigid surface and its respective nozzle from their ambient conditions.
5. The system of claim 4 , further comprising means for maintaining relative humidity within the environmental chamber below 40%.
6. The system of claim 4 , further comprising a moisture purging subsystem to replace at least some air within the environmental chamber with a dry gas.
7. The system of claim 6 , in which the dry gas is nitrogen.
8. The system of claim 1 , in which the heating system comprises an electroresistive heater connected to the rigid surface.
9. The system of claim 1 , in which the heating system comprises a convective heater connected to the rigid surface.
10. The system of claim 1 , in which the heating system causes air to flow to the rigid surface.
11. The system of claim 1 , in which the nozzle is directed toward the rigid surface at a forward angle with respect to tape direction.
12. The system of claim 1 , in which the nozzle is spaced from the tape by a distance greater than 1.27 mm and less than 19.05 mm.
13. The system of claim 1 , further comprising a manifold in which a plurality of the nozzles is located.
14. The system of claim 13 , in which the manifold is heated.
15. The system of claim 1 , further comprising a sub-system to direct heated air onto the tape immediately adjacent the impingement point.
16. The system of claim 15 , further comprising a manifold in which there is a plurality of nozzles, and in which the manifold comprises an outlet for directing the heated air onto the tape.
17. The system of claim 1 , further comprising at least one vacuum subsystem to remove debris from a vicinity of at least one impingement point.
18. The system of claim 1 , in which the system is one of a plurality of multiple carbon dioxide cleaning systems, any of which operates non-continuously while still providing continuous cleaning of the tape from a combined operation of the multiple systems.
19. A method of reducing condensation on data storage tape during carbon dioxide cleaning, comprising: a) supporting the tape under tension over a contact distance on at least one rigid surface; b) directing carbon dioxide, through at least one nozzle per rigid surface, at an impingement point within the contact distance of that rigid surface; c) maintaining surface temperature of the tape, as measured near each impingement point, above ambient dew point.
20. The method of claim 19 , in which the rigid surface comprises a material chosen from the group consisting essentially of nickel, iron, copper, beryllium, chromium, steel, zinc, aluminum, silver, magnesium, and their alloys.
21. The method of claim 19 , in which the rigid surface is a capstan and the contact distance is a wrapping angle.
22. The method of claim 19 , further comprising separating the rigid surface and its respective nozzle from their ambient conditions by an environmental chamber.
23. The method of claim 22 , further comprising maintaining relative humidity within the environmental chamber below 40%.
24. The method of claim 22 , further comprising replacing at least some air within the environmental chamber with a dry gas.
25. The method of claim 24 , in which the dry gas is nitrogen.
26. The method of claim 19 , in which maintaining the surface temperature of the tape comprises electroresistively heating the rigid surface.
27. The method of claim 19 , in which maintaining the surface temperature of the tape comprises convectively heating the rigid surface.
28. The method of claim 19 , in which maintaining the surface temperature of the tape comprises causing air to flow to the rigid surface.
29. The method of claim 19 , in which directing the carbon dioxide at the impingement point comprises directing the nozzle at a forward angle with respect to tape direction.
30. The method of claim 19 , in which directing the carbon dioxide at the impingement point comprises spacing the nozzle from the tape by a distance greater than 1.27 mm and less than 19.05 mm.
31. The method of claim 19 , further comprising locating a plurality of the nozzles in a manifold.
32. The method of claim 31 , further comprising heating the manifold.
33. The method of claim 19 , further comprising directing heated air onto the tape immediately adjacent the impingement point.
34. The method of claim 33 , further comprising locating a plurality of the nozzles in a manifold having an outlet for directing the heated air onto the tape.
35. The method of claim 19 , further comprising vacuuming debris from a vicinity of at least one impingement point.
36. The method of claim 19 , in which directing carbon dioxide from a nozzle occurs non-continuously while still providing continuous reducing of condensation on the tape from a combined operation of more than one nozzle.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
September 13, 2000
November 12, 2002
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